2 tbsp unsalted butter, melted
1 egg
grated zest of ¼ lemon
2 tbsp granulated sugar
¼ cup ground almonds or almond flour
2 tbsp all-purpose flour
¼ tsp baking powder
whipped cream, to serve (optional)
lemon curd, to serve (optional)
Find it online: https://misswish.com/lemon-mug-cake